The Clone Wars cartoon introduced the character of Ahsoka Tano, Anakin's apprentice, who was assigned to him by the Council shortly after his own knighting.
There are two parts to my curiosity:
A) Why/How/Since when did the council assign padawans to masters?
By all accounts so far, Jedi seem to choose their own apprentices - with the decision to do so or not, and the identity of the apprentice, both being initiated by the master-to-be. However, Ahsoka gets assigned to Anakin by the Council - until they meet he seems to be under the impression that the new Padawan is going to be Obi-Wan's apprentice.
So why was this apprenticeship initiated and assigned by the Council? Is this supposed to be the new canon/usual way of master-padawan selection or is it a special case? If the latter, why?
B) Why did the Council feel like it was a good idea to assign a Padawan to Anakin almost immediately after getting knighted?
Especially when this meant assigning a 14-year-old Padawan to a 19-year-old Knight, and furthermore a 19-year-old who was expected to be in the thick of things by virtue of his identity.
I'm looking for anything which might have been revealed in the series itself (I haven't watched it all) or which the creators might have said in interviews, at cons, etc.